Multi-technology coexistence for IBSS networks

ABSTRACT

Apparatus configured to be implemented in a first wireless communication device, having corresponding non-transitory computer-readable media, comprise a memory configured to store a coexistence schedule, wherein the coexistence schedule defines WLAN intervals and non-WLAN intervals; a WLAN transceiver configured to transmit WLAN signals in an IBSS network; a non-WLAN transceiver configured to transmit wireless non-WLAN signals; and a coexistence circuit configured to allow the WLAN transceiver to transmit the WLAN signals in the IBSS network only during the WLAN intervals, wherein the coexistence circuit is further configured to allow the non-WLAN transceiver to transmit the wireless non-WLAN signals only during the non-WLAN intervals; and wherein the coexistence circuit is further configured to cause the WLAN transceiver to transmit one or more coexistence request messages, each indicating a duration of at least one of a respective one of the WLAN intervals, and a respective one of the non-WLAN intervals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/481,079, filed on Apr. 29, 2011, entitled“WLAN/BT Coexistence Schemes for IBSS,” the disclosure thereofincorporated by reference herein in its entirety.

FIELD

The present disclosure relates generally to wireless communications.More particularly, the present disclosure relates to coexistence betweenwireless local-area networking (WLAN) signals and wireless non-WLANsignals.

BACKGROUND

The popularity of various wireless networking technologies for handheldplatforms has created a need to integrate multiple networkingtechnologies on a single wireless communication device. Of thesenetworking technologies, the two most widely used are wirelesslocal-area networking (WLAN) and Bluetooth. Both of these technologiesuse the same un-licensed 2.4 GHz Industrial, Scientific and Medical(ISM) band. This situation poses a difficult problem for designingintegrated circuits, external logic components, and wirelesscommunication devices that allow these technologies to coexist. BecauseBluetooth operates according to a known schedule, a multi-technologywireless communication device can schedule WLAN transmissions around theBluetooth transmissions. However, because the Bluetooth schedule is notknown to WLAN link partners, there are frequent collisions on thereceive side. These collisions can reduce WLAN performance to one-halfof baseline.

SUMMARY

In general, in one aspect, an embodiment features an apparatusconfigured to be implemented in a first wireless communication device,wherein the apparatus comprises: a memory configured to store acoexistence schedule, wherein the coexistence schedule defines wirelesslocal-area network (WLAN) intervals and non-WLAN intervals; a WLANtransceiver configured to transmit WLAN signals in an independent basicservice set (IBSS) network; a non-WLAN transceiver configured totransmit wireless non-WLAN signals; and a coexistence circuit configuredto allow the WLAN transceiver to transmit the WLAN signals in the IBSSnetwork only during the WLAN intervals, wherein the coexistence circuitis further configured to allow the non-WLAN transceiver to transmit thewireless non-WLAN signals only during the non-WLAN intervals; andwherein the coexistence circuit is further configured to cause the WLANtransceiver to transmit one or more coexistence request messages,wherein each of the coexistence request messages indicates a duration ofat least one of a respective one of the WLAN intervals, and a respectiveone of the non-WLAN intervals.

Embodiments of the apparatus can include one or more of the followingfeatures. In some embodiments, the IBSS network comprises one or moresecond wireless communication devices; and responsive to the one or morecoexistence request messages, the one or more second wirelesscommunication devices transmit no WLAN signals during the respectivenon-WLAN intervals. In some embodiments, the non-WLAN signals compriseat least one of: Bluetooth signals; near field communication (NFC)signals; FM signals; and GPS signals. In some embodiments, at least oneof the coexistence request messages comprises: a clear-to-send-to-selfframe, wherein the clear-to-send-to-self frame includes a durationparameter, wherein the duration parameter indicates the duration of therespective one of the non-WLAN intervals. In some embodiments, at leastone of the coexistence request messages comprises: a vendor-specificaction frame, wherein the vendor-specific action frame includes aduration parameter, wherein the duration parameter indicates theduration of the respective one of the non-WLAN intervals. In someembodiments, at least one of the coexistence request messages comprises:a vendor-specific action frame, wherein the vendor-specific action frameincludes a duration parameter, wherein the duration parameter indicatesthe duration of a period between a respective one of the non-WLANintervals and another one of the non-WLAN intervals. Some embodimentscomprise a wireless communication device comprising the apparatus. Insome embodiments, the wireless communication device is implemented asone of: a mobile telephone; a personal digital assistant (PDA); a tabletcomputer; and a personal computer. In some embodiments, the wirelesscommunication device is compliant with all or part of IEEE standard802.11, including draft and approved amendments such as 802.11a,802.11b, 802.11e, 802.11g, 802.11i, 802.11k, 802.11n, 802.11v, 802.11w,802.11aa, 802.11ac, 802.11ad, 802.11ae, 802.11af, 802.11ah, and802.11ai.

In general, in one aspect, an embodiment features non-transitorycomputer-readable media embodying instructions executable by a computerto perform functions comprising: storing a coexistence schedule, whereinthe coexistence schedule defines wireless local-area network (WLAN)intervals and non-WLAN intervals; allowing a WLAN transceiver totransmit WLAN signals in an independent basic service set (IBSS) networkonly during the WLAN intervals; allowing a non-WLAN transceiver totransmit wireless non-WLAN signals only during the non-WLAN intervals;and causing the WLAN transceiver to transmit one or more coexistencerequest messages, wherein each of the coexistence request messagesindicates a duration of at least one of a respective one of the WLANintervals, and a respective one of the non-WLAN intervals.

Embodiments of the non-transitory computer-readable media can includeone or more of the following features. In some embodiments, the IBSSnetwork comprises one or more second wireless communication devices; andresponsive to the one or more coexistence request messages, the one ormore second wireless communication devices transmit no WLAN signalsduring the respective non-WLAN intervals. In some embodiments, thenon-WLAN signals comprise at least one of: Bluetooth signals; near fieldcommunication (NFC) signals; FM signals; and GPS signals.

In general, in one aspect, an embodiment features an apparatusconfigured to be implemented in a first wireless communication device,wherein the apparatus comprises: a wireless local-area network (WLAN)transceiver configured to transmit WLAN signals in an independent basicservice set (IBSS) network, wherein the IBSS network comprises one ormore second wireless communication devices; and a coexistence circuitconfigured to allow the WLAN transceiver to transmit no WLAN signalsduring non-WLAN intervals responsive to the WLAN transceiver receivingcoexistence request messages, wherein each coexistence request messageindicates a duration of at least one of a respective one of the non-WLANintervals, and a period between a respective one of the non-WLANintervals and another one of the non-WLAN intervals.

Embodiments of the apparatus can include one or more of the followingfeatures. In some embodiments, the non-WLAN signals comprise at leastone of: Bluetooth signals; near field communication (NFC) signals; FMsignals; and GPS signals. In some embodiments, at least one of thecoexistence request messages comprises: a clear-to-send-to-self frame,wherein the clear-to-send-to-self frame includes a duration parameter,wherein the duration parameter indicates the duration of the respectiveone of the non-WLAN intervals. In some embodiments, at least one of thecoexistence request messages comprises: a vendor-specific action frame,wherein the vendor-specific action frame includes a duration parameter,wherein the duration parameter indicates a duration of the respectiveone of the non-WLAN intervals. In some embodiments, at least one of thecoexistence request messages comprises: a vendor-specific action frame,wherein the vendor-specific action frame includes a duration parameter,wherein the duration parameter indicates a duration of a period betweena respective one of the non-WLAN intervals and another one of thenon-WLAN intervals. Some embodiments comprise a wireless communicationdevice comprising the apparatus. In some embodiments, the wirelesscommunication device is implemented as one of: a mobile telephone; apersonal digital assistant (PDA); a tablet computer; and a personalcomputer. In some embodiments, the wireless communication device iscompliant with all or part of IEEE standard 802.11, including draft andapproved amendments such as 802.11a, 802.11b, 802.11e, 802.11g, 802.11i,802.11k, 802.11n, 802.11v, 802.11w, 802.11aa, 802.11ac, 802.11ad,802.11ae, 802.11af, 802.11ah, and 802.11ai.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 shows elements of a multi-technology wireless communicationsystem according to one embodiment.

FIG. 2 shows detail of the multi-technology wireless communicationdevice of FIG. 1 according to one embodiment.

FIG. 3 shows detail of a WLAN communication device of FIG. 1 accordingto one embodiment.

FIG. 4 illustrates a coexistence schedule according to one embodiment.

FIG. 5 shows the format of the CTS-to-self frame according to the IEEE802.11g standard.

FIG. 6 shows the timing of the transmission of the CTS-to-self frameswith reference to the coexistence schedule of FIG. 4 according to oneembodiment.

FIG. 7 shows a process for the multi-technology wireless communicationsystem of FIG. 1 according to the embodiment of FIG. 6.

FIG. 8 shows the format of the vendor-specific action frame according tothe IEEE 802.11 standard.

FIG. 9 shows the format of the vendor-specific information elementaccording to the IEEE 802.11 standard.

FIG. 10 shows the timing of the transmission of the vendor-specificaction frames with reference to the coexistence schedule of FIG. 4according to an embodiment where the duration parameter indicates theduration of the following Bluetooth interval.

FIG. 11 shows a process for the multi-technology wireless communicationsystem of FIG. 1 according to the embodiment of FIG. 10.

FIG. 12 shows the timing of the transmission of the vendor-specificaction frames with reference to the coexistence schedule of FIG. 4according to an embodiment where the duration parameter indicates theduration of the current WLAN interval.

FIG. 13 shows the format of the Unscheduled Automatic Power SaveDelivery (UAPSD) information element according to the IEEE 802.11standard.

FIG. 14 shows a process for the multi-technology wireless communicationsystem of FIG. 1 according to the embodiment of FIG. 13.

The leading digit(s) of each reference numeral used in thisspecification indicates the number of the drawing in which the referencenumeral first appears.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide coexistence formulti-technology wireless communication devices in an IEEE 802.11independent basic service set (IBSS) networks. In particular, in oneaspect, the disclosed embodiments describe coexistence for wirelesslocal-area networking (WLAN) and Bluetooth technologies. However, whilethe disclosed embodiments are described in terms of WLAN and Bluetoothtechnologies, the disclosed techniques are applicable to other wirelesstechnologies as well. The wireless technologies can include wirelessnon-WLAN signals other than Bluetooth. For example, the wirelessnon-WLAN signals can include near field communication (NFC) signals, FMsignals, GPS signals, other ISM band signals, and the like.

According to the described embodiments, a multi-technology wirelesscommunication device operates in an IBSS. The wireless technologiesinclude wireless local-area network (WLAN) and wireless non-WLANtechnologies. For example, the WLAN technology can be based on the IEEE802.11 standard, and the non-WLAN technology can include Bluetoothsignals, near field communication (NFC) signals, FM signals, GPSsignals, other ISM band signals, and the like. The multi-technologywireless communication device includes a WLAN transceiver configured totransmit WLAN signals during WLAN intervals, and a non-WLAN transceiverconfigured to transmit wireless non-WLAN signals during non-WLANintervals.

In accordance with one embodiment, a WLAN transceiver transmits acoexistence request message for each of the non-WLAN intervals. As usedherein, the term the term “message” generally refers to a wirelesselectronic signal representing a digital message. Each coexistencerequest message indicates a duration of a respective one of the WLANintervals, or a duration of a respective one of the non-WLAN intervals.In response to each coexistence request message, the other WLAN devicesin the IBSS transmit no WLAN signals during the respective non-WLANinterval. The result is reduction or elimination of interference betweenthe WLAN signals and the wireless non-WLAN signals.

FIG. 1 shows elements of a multi-technology wireless communicationsystem 100 according to one embodiment. Although in the describedembodiments the elements of multi-technology wireless communicationsystem 100 are presented in one arrangement, other embodiments mayfeature other arrangements. For example, elements of multi-technologywireless communication system 100 can be implemented in hardware,software, or combinations thereof.

Referring to FIG. 1, multi-technology wireless communication system 100includes a multi-technology wireless communication device 102, one ormore WLAN communication devices 104A-N, and a Bluetooth communicationdevice 106. Multi-technology wireless communication device 102 can beimplemented as any wireless communication device capable of performingthe functions described herein. For example, multi-technology wirelesscommunication device 102 can be implemented as a mobile telephone suchas a smartphone or feature phone, a personal digital assistant (PDA), atablet computer, a personal computer, or the like.

WLAN communication devices 104 can be implemented as any wirelesscommunication devices capable of performing the functions describedherein. For example, each WLAN communication device 104 can beimplemented as a mobile telephone such as a smartphone or feature phone,a personal digital assistant (PDA), a tablet computer, a personalcomputer, or the like. In addition, each WLAN communication device 104can be implemented as a multi-technology wireless communication device102, but this is not required.

Multi-technology wireless communication device 102 and WLANcommunication devices 104 form an independent basic service set (IBSS).That is, multi-technology wireless communication device 102 and WLANcommunication devices 104 communicate over an ad hoc WLAN 108. In someembodiments, ad hoc WLAN 108 is compliant with all or part of IEEEstandard 802.11, including draft and approved amendments such as802.11a, 802.11b, 802.11e, 802.11g, 802.11i, 802.11k, 802.11n, 802.11v,802.11w, 802.11aa, 802.11ac, 802.11ad, 802.11ae, 802.11af, 802.11ah, and802.11ai. Multi-technology wireless communication device 102communicates with Bluetooth communication device 106 over a wirelessBluetooth link 110.

FIG. 2 shows detail of multi-technology wireless communication device102 of FIG. 1 according to one embodiment. Although in the describedembodiments the elements of multi-technology wireless communicationdevice 102 are presented in one arrangement, other embodiments mayfeature other arrangements. For example, elements of multi-technologywireless communication device 102 can be implemented in hardware,software, or combinations thereof.

Referring to FIG. 2, multi-technology wireless communication device 102includes a WLAN transceiver 202, a Bluetooth transceiver 204, acoexistence circuit 206, a memory 212, and a timer 216. Coexistencecircuit 206 can be implemented as a processor. WLAN transceiver 202,Bluetooth transceiver 204, coexistence circuit 206, memory 212, andtimer 216 can be fabricated as one or more integrated circuits.

WLAN transceiver 202 transmits and receives (or transceives) WLANsignals 208 over ad hoc WLAN 108. Bluetooth transceiver 204 transceivesBluetooth signals 210 over Bluetooth link 110. Coexistence circuit 206schedules WLAN transceiver 202 and Bluetooth transceiver 204 to preventinterference between WLAN signals 208 and Bluetooth signals 210transmitted by multi-technology wireless communication device 102.Coexistence circuit 206 also causes WLAN transceiver 202 to transmitcoexistence request messages over ad hoc WLAN 108 to preventinterference between Bluetooth signals 210 and WLAN signals 208transmitted by WLAN communication devices 104. Memory 212 stores acoexistence schedule 214.

FIG. 3 shows detail of a WLAN communication device 104 of FIG. 1according to one embodiment. Although in the described embodiments theelements of WLAN communication device 104 are presented in onearrangement, other embodiments may feature other arrangements. Forexample, elements of WLAN communication device 104 can be implemented inhardware, software, or combinations thereof.

Referring to FIG. 3, WLAN communication device 104 includes a wirelesslocal-area network (WLAN) transceiver 302, a coexistence circuit 306,and a timer 316. Coexistence circuit 306 can be implemented as aprocessor. WLAN transceiver 302, coexistence circuit 306, and timer 316can be fabricated as one or more integrated circuits.

WLAN transceiver 302 transceives WLAN signals 208 over ad hoc WLAN 108.Coexistence circuit 306 schedules its WLAN transceiver 302 in accordancewith the coexistence request messages transmitted by multi-technologywireless communication device 102 to prevent interference between WLANsignals 208 transmitted by WLAN communication devices 104 and Bluetoothsignals 210.

Multi-technology wireless communication device 102 communicates withBluetooth communication device 106 over wireless Bluetooth link 110according to coexistence schedule 214 and timer 216. FIG. 4 illustratesa coexistence schedule 214 according to one embodiment. Coexistenceschedule 214 consists of Bluetooth intervals 402 and WLAN intervals 404.In general, the schedule is periodic, so that all Bluetooth intervals402 have the same duration Tbt, and so that all WLAN intervals 404 havethe same duration Twlan. However, this periodicity is not required. Ingeneral, the duration Twlan of WLAN intervals 404 is greater than theduration Tbt of Bluetooth intervals 402, but this is not required.

Coexistence schedule 214 is known to multi-technology wirelesscommunication device 102. Therefore coexistence circuit 206 can controlthe transmissions of WLAN transceiver 202 and Bluetooth transceiver 204deterministically according to coexistence schedule 214 and timer 216 soas to avoid interference between the transmissions. In particular,coexistence circuit 206 allows WLAN transceiver 202 to transmit WLANsignals 208 only during WLAN intervals 404, and allows Bluetoothtransceiver 204 to transmit Bluetooth signals 210 only during Bluetoothintervals 402.

However, coexistence schedule 214 is not known to WLAN communicationdevices 104. To prevent interference between the transmissions of WLANcommunication devices 104 and Bluetooth signals 210, coexistence circuit206 of multi-technology wireless communication device 102 causes WLANtransceiver 202 to transmit coexistence request messages. Eachcoexistence request message indicates a duration of one of the WLANintervals 404, or a duration of one of the Bluetooth intervals 402. Ateach WLAN communication device 104, responsive to the WLAN transceiver302 receiving a coexistence request message, coexistence circuit 306allows the WLAN transceiver 302 to transmit no WLAN signals 208 duringone of the Bluetooth intervals 402. Bluetooth communication device 106has knowledge of coexistence schedule 214, and so transmits Bluetoothsignals 210 only during Bluetooth intervals 402.

In some embodiments, the coexistence request message is implemented as aclear-to-send-to-self (CTS-to-self) frame. FIG. 5 shows the format ofthe CTS-to-self frame according to the IEEE 802.11g standard. TheCTS-to-self frame includes a two-octet Frame Control field, a two-octetDuration field, a six-octet Receiver Address (RA) field, and afour-octet Frame Check Sequence (FCS) field. The RA field contains theMAC address of multi-technology wireless communication device 102. Theduration field contains a duration parameter that indicates the durationof the next Bluetooth interval 402.

FIG. 6 shows the timing of the transmission of the CTS-to-self frameswith reference to coexistence schedule 214 of FIG. 4 according to oneembodiment. Referring to FIG. 6, coexistence circuit 206 ofmulti-technology wireless communication device 102 causes WLANtransceiver 202 to transmit a CTS-to-self frame 602 just prior to thestart of each Bluetooth interval 402. The duration parameter of eachCTS-to-self frame 602 indicates the duration of the subsequent Bluetoothinterval 402. WLAN transceivers 302 of WLAN communication devices 104receive CTS-to-self frames 602.

At each WLAN communication device 104, responsive to the WLANtransceiver 302 receiving a CTS-to-self frame 602, coexistence circuit306 allows the WLAN transceiver 302 to transmit no WLAN signals 208 forthe interval specified by the duration parameter in that CTS-to-selfframe 602. That is, coexistence circuit 306 allows the WLAN transceiver302 to transmit no WLAN signals 208 during the subsequent Bluetoothinterval 402.

FIG. 7 shows a process 700 for multi-technology wireless communicationsystem 100 of FIG. 1 according to the embodiment of FIG. 6. Although inthe described embodiments the elements of process 700 are presented inone arrangement, other embodiments may feature other arrangements. Forexample, in various embodiments, some or all of the elements of process700 can be executed in a different order, concurrently, and the like.Also some elements of process 700 may not be performed, and may not beexecuted immediately after each other. FIG. 7 is arranged in twocolumns, with processes of multi-technology wireless communicationdevice 102 shown in the left-hand column, and with processes of a WLANcommunication device 104 shown in the right-hand column.

Referring to FIG. 7, at 702 and 704, a WLAN interval 404 begins. DuringWLAN interval 404, WLAN transmission is allowed for bothmulti-technology wireless communication device 102 and WLANcommunication device 104. At 706, multi-technology wirelesscommunication device 102 determines when the WLAN interval 404 isending. In particular, coexistence circuit 206 of multi-technologywireless communication device 102 consults the coexistence schedule 214stored in memory 212 and timer 216. At 708, just prior to the end of theWLAN interval 404, multi-technology wireless communication device 102transmits a CTS-to-self frame 602 that includes the duration of thefollowing Bluetooth interval 402. Then the Bluetooth interval 402begins. Coexistence circuit 206 does not allow WLAN transmission bymulti-technology wireless communication device 102 during Bluetoothinterval 402.

At 710, WLAN communication device 104 receives the CTS-to-self frame602, and gets the duration of the Bluetooth interval 402 from that frame602. Bluetooth interval 402 begins. Coexistence circuit 306 does notallow WLAN transmission by WLAN communication device 104 duringBluetooth interval 402.

At 712, multi-technology wireless communication device 102 determineswhen the Bluetooth interval 402 has ended. In particular, coexistencecircuit 206 of multi-technology wireless communication device 102consults timer 216 and the coexistence schedule 214 stored in memory212. When the Bluetooth interval 402 ends, the next WLAN interval beginsat 702. Coexistence circuit 206 allows WLAN transmission bymulti-technology wireless communication device 102 during WLAN interval404.

At 714, WLAN communication device 104 determines when the peer'sBluetooth interval 402 has ended (that is, when the Bluetooth interval402 for multi-technology wireless communication device 102 has ended).In particular, coexistence circuit 306 of WLAN communication device 104uses timer 316 and the duration from the CTS-to-self frame 602 todetermine when the peer's Bluetooth interval 402 has ended. When thepeer's Bluetooth interval 402 ends, the next WLAN interval begins at704. Coexistence circuit 306 allows WLAN transmission by WLANcommunication device 104 during WLAN interval 404.

In some embodiments, the coexistence request message is implemented as avendor-specific action frame, where the vendor-specific action frameincludes a duration parameter. The coexistence request message can alsobe sent using beacons and probe request/response messages when possible.In some embodiments, the duration parameter indicates the duration ofthe following Bluetooth interval 402. In other embodiments, the durationparameter indicates the duration of the current WLAN interval 404.

FIG. 8 shows the format of the vendor-specific action frame according tothe IEEE 802.11 standard. Referring to FIG. 8, the vendor-specificaction frame includes a one-octet Category field, a three-octet OUIfield, and a variable-length Vendor-Specific Content field. The Categoryfield is set to the value indicating the vendor-specific category. TheOUI field contains a public OUI, assigned by the IEEE, of the entitythat has defined the content of the particular vendor-specific action.The Vendor-Specific Content field contains one or more vendor-specificfields. In the described embodiment, the Vendor-Specific Content fieldcontains the vendor-specific information element.

In some embodiments, the vendor-specific action frame includes avendor-specific information element that includes the durationparameter. FIG. 9 shows the format of the vendor-specific informationelement according to the IEEE 802.11 standard. Referring to FIG. 9, thevendor-specific information element includes a one-octet Element IDfield, a one-octet Length field, a three-octet OUI field, and avariable-length Vendor-Specific Content field. The Element ID fieldindicates the information element is a vendor-specific informationelement. The OUI field contains a public OUI assigned by the IEEE. TheVendor-Specific Content field contains one or more vendor-specificfields. In the described embodiment, the Vendor-Specific Content fieldcontains the duration parameter. In other embodiments, thevendor-specific action frame includes a WiFi Direct Notice of Absenceelement that includes the duration parameter.

FIG. 10 shows the timing of the transmission of the vendor-specificaction frames with reference to coexistence schedule 214 of FIG. 4according to an embodiment where the duration parameter indicates theduration of the following Bluetooth interval 402. Referring to FIG. 10,coexistence circuit 206 of multi-technology wireless communicationdevice 102 causes WLAN transceiver 202 to transmit a vendor-specificaction frame 1002 just prior to the start of each Bluetooth interval402. The duration parameter of each vendor-specific action frame 1002indicates the duration of the subsequent Bluetooth interval 402. WLANtransceivers 302 of WLAN communication devices 104 receive thevendor-specific action frames 1002.

At each WLAN communication device 104, responsive to the WLANtransceiver 302 receiving a vendor-specific action frame 1002,coexistence circuit 306 allows the WLAN transceiver 302 to transmit noWLAN signals 208 for the interval specified by the duration parameter inthat vendor-specific action frame 1002. That is, coexistence circuit 306allows the WLAN transceiver 302 to transmit no WLAN signals 208 duringthe subsequent Bluetooth interval 402.

FIG. 11 shows a process 1100 for multi-technology wireless communicationsystem 100 of FIG. 1 according to the embodiment of FIG. 10. Although inthe described embodiments the elements of process 1100 are presented inone arrangement, other embodiments may feature other arrangements. Forexample, in various embodiments, some or all of the elements of process1100 can be executed in a different order, concurrently, and the like.Also some elements of process 1100 may not be performed, and may not beexecuted immediately after each other. FIG. 11 is arranged in twocolumns, with processes of multi-technology wireless communicationdevice 102 shown in the left-hand column, and with processes of a WLANcommunication device 104 shown in the right-hand column.

Referring to FIG. 11, at 1102 and 1104, a WLAN interval 404 begins.During WLAN interval 404, WLAN transmission is allowed for bothmulti-technology wireless communication device 102 and WLANcommunication device 104. At 1106, multi-technology wirelesscommunication device 102 determines when the WLAN interval 404 isending. In particular, coexistence circuit 206 of multi-technologywireless communication device 102 consults the coexistence schedule 214stored in memory 212 and timer 216. At 1108, prior to the end of theWLAN interval 404, multi-technology wireless communication device 102transmits a vendor-specific action frame 1002 that includes the durationof the following Bluetooth interval 402. Then the Bluetooth interval 402begins. Coexistence circuit 206 does not allow WLAN transmission bymulti-technology wireless communication device 102 during Bluetoothinterval 402.

At 1110, WLAN communication device 104 receives the vendor-specificaction frame 1002, and gets the duration of the Bluetooth interval 402from that frame 1002. Bluetooth interval 402 begins. Coexistence circuit306 does not allow WLAN transmission by WLAN communication device 104during Bluetooth interval 402.

At 1112, multi-technology wireless communication device 102 determineswhen the Bluetooth interval 402 has ended. In particular, coexistencecircuit 206 of multi-technology wireless communication device 102consults timer 216 and the coexistence schedule 214 stored in memory212. When the Bluetooth interval 402 ends, the next WLAN interval beginsat 1102. Coexistence circuit 206 allows WLAN transmission bymulti-technology wireless communication device 102 during WLAN intervals404.

At 1114, WLAN communication device 104 determines when the peer'sBluetooth interval 402 has ended (that is, when the Bluetooth interval402 for multi-technology wireless communication device 102 has ended).In particular, coexistence circuit 306 of WLAN communication device 104uses timer 316 and the duration from the vendor-specific action frame1002 to determine when the peer's Bluetooth interval 402 has ended. Whenthe peer's Bluetooth interval 402 ends, the next WLAN interval 404begins at 1104. Coexistence circuit 306 allows WLAN transmission by WLANcommunication device 104 during WLAN intervals 404.

FIG. 12 shows the timing of the transmission of the vendor-specificaction frames with reference to coexistence schedule 214 of FIG. 4according to an embodiment where the duration parameter indicates theduration of the current WLAN interval 404. Referring to FIG. 12,coexistence circuit 206 of multi-technology wireless communicationdevice 102 causes WLAN transceiver 202 to transmit a vendor-specificaction frame 1202 at the start of each WLAN interval 404. The durationparameter of each vendor-specific action frame 1202 indicates theduration of that WLAN interval 404. WLAN transceivers 302 of WLANcommunication devices 104 receive vendor-specific action frames 1202.

At each WLAN communication device 104, responsive to the WLANtransceiver 302 receiving a vendor-specific action frame 1202,coexistence circuit 306 allows the WLAN transceiver 302 to transmit WLANsignals 208 only during the interval specified by the duration parameterin that vendor-specific action frame 1202. That is, coexistence circuit306 allows the WLAN transceiver 302 to transmit WLAN signals 208 onlyduring that WLAN interval 404.

In some embodiments, the vendor-specific action frame includes anUnscheduled Automatic Power Save Delivery (UAPSD) information elementthat includes the duration parameter. FIG. 13 shows the format of theUAPSD information element according to the IEEE 802.11 standard.Referring to FIG. 13, the UAPSD information element includes a one-octetElement ID field, a one-octet Length field, an eight-octet TSF 0 Offsetfield, a four-octet Interval/Duration field, and a variable-lengthOptional Subelements field.

The Element ID field contains a predetermined value that identifies theinformation element as being the UAPSD information element. The value ofthe Length field is 12 plus the length of any additional subelementspresent. The TSF 0 Offset field is not required in this embodiment. TheInterval/Duration field contains the duration parameter. The OptionalSubelements field format contains zero or more subelements.

FIG. 14 shows a process 1400 for multi-technology wireless communicationsystem 100 of FIG. 1 according to the embodiment of FIG. 13. Although inthe described embodiments the elements of process 1400 are presented inone arrangement, other embodiments may feature other arrangements. Forexample, in various embodiments, some or all of the elements of process1400 can be executed in a different order, concurrently, and the like.Also some elements of process 1400 may not be performed, and may not beexecuted immediately after each other. FIG. 14 is arranged in twocolumns, with processes of multi-technology wireless communicationdevice 102 shown in the left-hand column, and with processes of a WLANcommunication device 104 shown in the right-hand column.

Referring to FIG. 14, at 1402 and 1404, a Bluetooth interval 402 beginsfor multi-technology wireless communication device 102. During Bluetoothinterval 402, WLAN transmission is not allowed for eithermulti-technology wireless communication device 102 or WLAN communicationdevice 104. At 1406, multi-technology wireless communication device 102determines when the Bluetooth interval 402 has ended. In particular,coexistence circuit 206 of multi-technology wireless communicationdevice 102 consults the coexistence schedule 214 stored in memory 212and timer 216. At 1408, after the end of the Bluetooth interval 402,multi-technology wireless communication device 102 transmits avendor-specific action frame 1302 that includes the duration of thecurrent WLAN interval 404. Coexistence circuit 206 allows WLANtransmission by multi-technology wireless communication device 102 onlyduring WLAN intervals 404.

At 1410, WLAN communication device 104 receives the vendor-specificaction frame 1302, and gets the duration of the WLAN interval 404 fromthat frame 1302. WLAN interval 404 has begun. Coexistence circuit 306allows WLAN transmission by WLAN communication device 104 only duringWLAN intervals 404.

At 1412, multi-technology wireless communication device 102 determineswhen the WLAN interval 404 has ended. In particular, coexistence circuit206 of multi-technology wireless communication device 102 consults timer216 and the coexistence schedule 214 stored in memory 212. When the WLANinterval 404 ends, the next Bluetooth interval begins at 1402.Coexistence circuit 206 does not allow WLAN transmission bymulti-technology wireless communication device 102 during Bluetoothintervals 402.

At 1414, WLAN communication device 104 determines when the WLAN interval404 has ended. In particular, coexistence circuit 306 of WLANcommunication device 104 uses timer 316 and the duration from thevendor-specific action frame 1302 to determine when the WLAN interval404 has ended. When the WLAN interval 404 ends, the next Bluetoothinterval 402 begins at 1404. Coexistence circuit 306 doe not allow WLANtransmission by WLAN communication device 104 during Bluetooth intervals402.

Multiple embodiments have been described using CTS-to-self frames andvendor-specific action frames. In some devices, only one of theseembodiments are implemented. In other devices, two or more of theseembodiments are implemented, and are selected dynamically according tofactors such as network conditions. For example, embodiments that employCTS-to-self frames can be selected when the IBSS includes only onemulti-technology wireless communication device 102 and one WLANcommunication device 104 and no other IBSS is nearby. As anotherexample, embodiments that employ vendor-specific action frames can beselected when the IBSS includes multiple WLAN communication devices 104.

Various embodiments of the present disclosure can be implemented indigital electronic circuitry, or in computer hardware, firmware,software, or in combinations thereof. Embodiments of the presentdisclosure can be implemented in a computer program product tangiblyembodied in a computer-readable storage device for execution by aprogrammable processor. The described processes can be performed by aprogrammable processor executing a program of instructions to performfunctions by operating on input data and generating output. Embodimentsof the present disclosure can be implemented in one or more computerprograms that are executable on a programmable system including at leastone programmable processor coupled to receive data and instructionsfrom, and to transmit data and instructions to, a data storage system,at least one input device, and at least one output device. Each computerprogram can be implemented in a high-level procedural or object-orientedprogramming language, or in assembly or machine language if desired; andin any case, the language can be a compiled or interpreted language.Suitable processors include, by way of example, both general and specialpurpose microprocessors. Generally, processors receive instructions anddata from a read-only memory and/or a random access memory. Generally, acomputer includes one or more mass storage devices for storing datafiles. Such devices include magnetic disks, such as internal hard disksand removable disks, magneto-optical disks; optical disks, andsolid-state disks. Storage devices suitable for tangibly embodyingcomputer program instructions and data include all forms of non-volatilememory, including by way of example semiconductor memory devices, suchas EPROM, EEPROM, and flash memory devices; magnetic disks such asinternal hard disks and removable disks; magneto-optical disks; andCD-ROM disks. Any of the foregoing can be supplemented by, orincorporated in, ASICs (application-specific integrated circuits).

A number of implementations have been described. Nevertheless, variousmodifications may be made without departing from the scope of thedisclosure. Accordingly, other implementations are within the scope ofthe following claims.

What is claimed is:
 1. An apparatus configured to be implemented in afirst wireless communication device, wherein the apparatus comprises: amemory configured to store a coexistence schedule, wherein thecoexistence schedule defines wireless local-area network (WLAN)intervals and non-WLAN intervals; a WLAN transceiver configured totransmit WLAN signals in an independent basic service set (IBSS)network; a non-WLAN transceiver configured to transmit wireless non-WLANsignals; and a coexistence circuit configured to allow the WLANtransceiver to transmit the WLAN signals in the IBSS network only duringthe WLAN intervals, wherein the coexistence circuit is furtherconfigured to allow the non-WLAN transceiver to transmit the wirelessnon-WLAN signals only during the non-WLAN intervals; and wherein thecoexistence circuit is further configured to cause the WLAN transceiverto transmit a coexistence request message, prior to each of the non-WLANintervals, to one or more second wireless communication devices in theIBSS network, wherein each of the coexistence request messages indicatesa duration of a respective one of the non-WLAN intervals, to prevent theone or more second wireless communication devices from transmittingduring the respective one of the non-WLAN intervals.
 2. The apparatus ofclaim 1, wherein the non-WLAN signals comprise at least one of:Bluetooth signals; near field communication (NFC) signals; FM signals;and GPS signals.
 3. The apparatus of claim 1, wherein at least one ofthe coexistence request messages comprises: a clear-to-send-to-selfframe, wherein the clear-to-send-to-self frame includes a durationparameter, wherein the duration parameter indicates the duration of therespective one of the non-WLAN intervals.
 4. The apparatus of claim 1,wherein at least one of the coexistence request messages comprises: avendor-specific action frame, wherein the vendor-specific action frameincludes a duration parameter, wherein the duration parameter indicatesthe duration of the respective one of the non-WLAN intervals.
 5. Theapparatus of claim 1, wherein at least one of the coexistence requestmessages comprises: a vendor-specific action frame, wherein thevendor-specific action frame includes a duration parameter, wherein theduration parameter indicates the duration of a period between arespective one of the non-WLAN intervals and another one of the non-WLANintervals.
 6. A wireless communication device comprising the apparatusof claim
 1. 7. The wireless communication device of claim 6, wherein thewireless communication device is implemented as one of: a mobiletelephone; a personal digital assistant (PDA); a tablet computer; and apersonal computer.
 8. The wireless communication device of claim 6,wherein the wireless communication device is compliant with all or partof IEEE standard 802.11, including draft and approved amendments such as802.11a, 802.11b, 802.11e, 802.11g, 802.11i, 802.11k, 802.11n, 802.11v,802.11w, 802.11aa, 802.11ac, 802.11ad, 802.11ae, 802.11af, 802.11ah, and802.11ai.
 9. Non-transitory computer-readable media embodyinginstructions executable by a computer to perform functions comprising:storing a coexistence schedule, wherein the coexistence schedule defineswireless local-area network (WLAN) intervals and non-WLAN intervals;allowing a WLAN transceiver to transmit WLAN signals in an independentbasic service set (IBSS) network only during the WLAN intervals;allowing a non-WLAN transceiver to transmit wireless non-WLAN signalsonly during the non-WLAN intervals; and causing the WLAN transceiver totransmit a coexistence request message, prior to each of the non-WLANintervals, to one or more second wireless communication devices in theIBSS network, wherein each of the coexistence request messages indicatesa duration of a respective one of the non-WLAN intervals, to prevent theone or more second wireless communication devices from transmittingduring the respective one of the non-WLAN intervals.
 10. Thenon-transitory computer-readable media of claim 9, wherein the non-WLANsignals comprise at least one of: Bluetooth signals; near fieldcommunication (NFC) signals; FM signals; and GPS signals.
 11. Anapparatus configured to be implemented in a first wireless communicationdevice, wherein the apparatus comprises: a wireless local-area network(WLAN) transceiver configured to transmit WLAN signals in an independentbasic service set (IBSS) network, wherein the IBSS network comprises oneor more second wireless communication devices; and a coexistence circuitconfigured to allow the WLAN transceiver to transmit no WLAN signalsduring non-WLAN intervals responsive to the WLAN transceiver receivingcoexistence request messages, wherein each coexistence request message(i) is received by the coexistence circuit, from the one or more secondwireless communication devices, prior to each of the non-WLAN intervals,and (ii) indicates a duration of at least one of a respective one of thenon-WLAN intervals, and a period between a respective one of thenon-WLAN intervals and another one of the non-WLAN intervals.
 12. Theapparatus of claim 11, wherein the non-WLAN signals comprise at leastone of: Bluetooth signals; near field communication (NFC) signals; FMsignals; and GPS signals.
 13. The apparatus of claim 11, wherein atleast one of the coexistence request messages comprises: aclear-to-send-to-self frame, wherein the clear-to-send-to-self frameincludes a duration parameter, wherein the duration parameter indicatesthe duration of the respective one of the non-WLAN intervals.
 14. Theapparatus of claim 11, wherein at least one of the coexistence requestmessages comprises: a vendor-specific action frame, wherein thevendor-specific action frame includes a duration parameter, wherein theduration parameter indicates a duration of the respective one of thenon-WLAN intervals.
 15. The apparatus of claim 11, wherein at least oneof the coexistence request messages comprises: a vendor-specific actionframe, wherein the vendor-specific action frame includes a durationparameter, wherein the duration parameter indicates a duration of aperiod between a respective one of the non-WLAN intervals and anotherone of the non-WLAN intervals.
 16. A wireless communication devicecomprising the apparatus of claim
 11. 17. The wireless communicationdevice of claim 16, wherein the wireless communication device isimplemented as one of: a mobile telephone; a personal digital assistant(PDA); a tablet computer; and a personal computer.
 18. The wirelesscommunication device of claim 16, wherein the wireless communicationdevice is compliant with all or part of IEEE standard 802.11, includingdraft and approved amendments such as 802.11a, 802.11b, 802.11e,802.11g, 802.11i, 802.11k, 802.11n, 802.11v, 802.11w, 802.11aa,802.11ac, 802.11ad, 802.11ae, 802.11af, 802.11ah, and 802.11ai.